Subject: Re: [PATCH iproute2 1/2] mptcp: monitor: also show iface name

From: Stephen Hemminger <[email-masked]>
Date: Thu, 19 Feb 2026 09:11:01 -0800

On Wed, 18 Feb 2026 20:03:20 +0100
Matthieu Baerts <[email-masked]> wrote:

> Hi Stephen,
> 
> Thank you for the review!
> 
> On 18/02/2026 19:31, Stephen Hemminger wrote:
> > On Wed, 11 Feb 2026 13:03:17 +0100
> > "Matthieu Baerts (NGI0)" <[email-masked]> wrote:
> >   
> >> @@ -530,7 +541,7 @@ static int mptcp_monitor_msg(struct rtnl_ctrl_data *ctrl,
> >>  	if (tb[MPTCP_ATTR_TIMEOUT])
> >>  		printf(" timeout=%u", rta_getattr_u32(tb[MPTCP_ATTR_TIMEOUT]));
> >>  	if (tb[MPTCP_ATTR_IF_IDX])
> >> -		printf(" ifindex=%d", rta_getattr_s32(tb[MPTCP_ATTR_IF_IDX]));
> >> +		print_iface(rta_getattr_s32(tb[MPTCP_ATTR_IF_IDX]));
> >>  	if (tb[MPTCP_ATTR_RESET_REASON])
> >>  		printf(" reset_reason=%u", rta_getattr_u32(tb[MPTCP_ATTR_RESET_REASON]));
> >>  	if (tb[MPTCP_ATTR_RESET_FLAGS])  
> > 
> > 
> > The whole monitor message output format here is divergent from what other
> > iproute2 commands do. If you look at ip monitor there are no '=' signs
> > in the output.  
> 
> Indeed, the output is different from 'ip monitor' (but similar to 'ip
> ioam monitor').

IMHO ioam monitor is outlier as well. Should have seen that during review.

> 
> > Please fix the whole function.  
> 
> Doing that would likely break scripts parsing 'ip mptcp monitor' output,
> are you sure we should still change this output format?

I doubt scripts are parsing this weird format. That is one more reason for JSON